solution.py

# Definition for a binary tree node.
# class TreeNode(object):
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None

class Solution(object):
    def __init__(self):
        self.result = []
        self.current_level = 0
        self.max_level = self.current_level
    def rightSideView(self, root):
        """
        :type root: TreeNode
        :rtype: List[int]
        """
        if root == None:
            return self.result
        
        if self.current_level >= self.max_level:
            self.result.append(root.val)
        self.current_level += 1
        self.max_level = max(self.current_level, self.max_level)
        self.rightSideView(root.right)
        self.rightSideView(root.left)
        self.current_level -= 1
        return self.result